Method for conductance switching in molecular electronic junctions

Abstract

The present invention includes a chemical monolayer construction that comprises: a substrate having a contact surface, and a monolayer of a plurality of substantially parallel molecular units attached to the contact surface of the substrate. The molecular units are strongly coupled electronically to the substrate. The contact surface of the substrate has a roughness value less than or equal to the average length of the molecular units. The molecular units comprise a chemical structure that is capable of being changed from a relatively non-conductive state to a relatively conductive state by the application of a stimulus. The present invention also includes electronic circuit components and devices including chemical monolayer constructions.

Description

[0002]The present application claims priority to U.S. provisional application No. 60 / 365,465, filed Mar. 19, 2002 and to U.S. provisional application No. 60 / 405,397, filed Aug. 23, 2002, both of which are hereby incorporated in their entirety by reference.[0003]The present invention was made with Government support under Grant No. RF 737159 awarded by the National Science Foundation. The United States Government may have certain rights to this invention under 35 U.S.C. §200 et seq.TECHNICAL FIELD OF THE INVENTION[0004]The present invention is in the field of chemical monolayers and microelectronic junctions, and includes chemical sensors, photosensors, electrochemical devices, memory devices, and other devices containing them.BACKGROUND OF THE INVENTION[0005]Conductance switching is the basis of many potential molecular electronic devices, and has been the focus of numerous research efforts in recent years. If a single molecule or an assembly of molecules can be switched between a h...

AI Technical Summary

Benefits of technology

[0019]Compatibility with conventional

Problems solved by technology

Although several examples of conductance switching have been extensively investigated, the switching mechanism in most cases is unknown, and the subject of some controversy.

The mechanism is controversial and the chemical requirements for a successful molecular switch are unknown.

Single molecule or nanoscale electronic devices hold exceptional promise for technical and economic value, but also present formidable hurdles for practical utility, and massively parallel fabrication.

Although the gold / thiol and Langmuir-Blodgett structures used to fabricate these molecular devices have been widely studied, they have yet to yield a commercial electronic product.

First, the Au / thiol SAM is widely studied and relatively simple to prepare, but is prone to pinholes generally limiting SAM devices to small areas (˜30×20 nm).

Second, the relatively weak interactions responsible for orienting Au / thiol and Langmuir-Blodgett (LB) structures are thermodynamically prone to disordering, since the bond energies are 40 kcal / mole or less (about 1.6 eV).

Third, both Au / thiol and LB structures result in an energy barrier between the conductor and the molecule.

No structure yet reported has an ohmic contact between molecule and conductor, thus hindering the inclusion of molecular properties into an electronic circuit.

Fourth, molecular devices with sizes below the current lithographic limit (˜100 nm) are difficult to fabricate in a massively parallel device, at least with any currently available methods.

Images